The articles entitled "Automated Welding of Turbine Blades", 1989, and "Integrated Weld Automation for Gas Turbine Engine Blades", 1991, published by The American Society Of Mechanical Engineers describe welding of turbine blade tips for repair purposes. Usually, in blade tip repair, multiple weld beads of a suitable material are laid down one atop the other on the turbine blade tip to build it up to desired dimension. The presence of an uneven wall (thin) region on the turbine blade tip or previously deposited bead can cause the welding torch to burn through the blade tip or the previously deposited bead, resulting in an unacceptable repair.
An object of the present invention is to provide a variable control system that can detect a surface irregularity on a substrate, such as a turbine blade tip, and automatically adjust a weld parameter to accommodate and level the surface irregularity and avoid weld burn through of the substrate or a previously deposited weld bead on the substrate.